I'm working improving the payroll package in my company's not-for-profit accounting software, and I thought it might be nice to add automatic calculation for federal and state withholdings. I figured that someone might have an API available which would return the appropriate tax tables in some sort of generalized fashion, but I've been unable to find the only such service, whether freemium or commercial has been the one at http://www.suburbancomputer.com/tips_state_tax.php which does not appear to offer any sort of API, but simply consolidated and compressed tax tables.<p>Does HN know of any such service?
Some further searching led to at least one additional result. In addition to Suburban Computer Services (<a href="http://www.suburbancomputer.com/tips_state_tax.php" rel="nofollow">http://www.suburbancomputer.com/tips_state_tax.php</a>), there is the Symmetry Tax Engine (<a href="https://www.symmetry.com/pages/ste.php" rel="nofollow">https://www.symmetry.com/pages/ste.php</a>). It's not a web service, but rather a library that you can integrate into your application. Pricing starts at $17,500 for up to 50,000 W-2s.
Sounds like a good Gov2.0 open data project.<p>This may be a good start for someone who finds time to build one =)
<a href="http://www.irs.gov/pub/irs-pdf/n1036.pdf" rel="nofollow">http://www.irs.gov/pub/irs-pdf/n1036.pdf</a>